Hey everyone,

I posted this elsewhere but I figured maybe it might be better to post on a hardware store forum than a programming forum. Essentially I get an error: "CMOS CHECKSUM BAD" when I try to boot to floppy, CD or HD. If I try to access the BIOS, same thing. For more details my original post is here: http://forums.devshed.com/motherboards-106/asus-a8v-cmos-bad-checksum-643399.html

Has anyone had any problems with this particular board? Does anyone know of any solutions? I've probably flashed it with the v1 image from the motherboard CD about half a dozen times now. I've tried everything I can think of aside from trying a different PSU and a different motherboard. The RAM, video and HD have been tested in another system and work. I don't have a 939 board to test the CPU on and I'm a bit too lazy to be going around switching PSUs this late. I will try another PSU I have in another system if it has the extra 4-pin power plug and let you know how it works out.

The upside to this story is I got the system for free for helping my neighbor move. When I first got it I couldn't get anything on the screen, not even POST.

The battery on the MOBO is probably dead or low, should try replacing that.

I tried that, used a battery from a working system. No luck.

Did the jumper fall off or get switched?

more cmos problems...

No the jumper was in tact. The system had a little bit of dust starting to gather on the fan blade edges but there wasn't much dust in the system. I did notice that on the keyboard power jumper it looked like the dust may be shorting, but since the jumper was on pins 1 and 2 I didn't see this as likely.

I took apart the entire system, mainly because it only had 4 posts holding the motherboard to the case when it had holes for 9.

I tested the video, ram and HD in another system and they worked fine. I didn't run memtest86 on the ram though. I tried another stick of ram from another system. I tried another battery. I followed the manuals procedure for resetting the CMOS to factory defaults. The process says: Remove power/plug. Remove battery. Move jumper from pins 1-2 to pins 2-3 for 5-10 seconds. Replace jumper to original location. Replace battery. Plug in system and turn it on. This is what got me to the point that I could actually see POST on my monitor. I downloaded the latest BIOS from ASUS and put it onto a floppy to use with EZ-Flash. The EZ-Flash program said that it couldn't find the file. I put in the CD rom and removed the floppy and then retried to flash the BIOS with the original v1.07 BIOS. Current version is 2.29. This process worked with the CD-ROM BIOS image. Even though the process reports working, and it very well may, I still get the CMOS checksum bad error.

I tried another floppy since the floppy I was using came with the system and was a bit noisy during reads and writes. The other floppy I had used to flash my current systems BIOS a few weeks ago using an open source implementation of DOS. Could be the floppy drive, the cable or anything.

The CPU in the system is a 3500+ Athlon64. I'm not sure if this CPU is supported under the original BIOS. Could this cause the issue? Is anyone willing to put a supported CPU into my mobo so I can flash with a more recent, CPU supporting, BIOS? lol

Anyway, I'm going to keep trying to fix this until I've exhausted every resource I have. I'm going to try to put the latest BIOS onto a DVD and hope that the EZ-Flash utility can use a DVD when it searches the CD-ROM.

Thought I'd update you all. I tried half of the BIOS updates on the website and all of them give me ERROR! ROMID is not compatible with BIOS ROMID! If I enter the motherboard CD-ROM that says A8V on it it will read the A8V.ROM file from it and flash the bios but that doesn't get rid of the CMOS CHECKSUM BAD error. If I clear the CMOS the only difference is that I get a new error message saying the CMOS date/time isn't set, as expected.

So I went to the ASUS forums and found a thread, motherboard troubleshooting - to try and figure out what I'm doing wrong. I can't find my little speaker so I'm just going to use the case speaker. I get the beep codes fine.

I'm amazed at how many people have had this issue with this particular motherboard yet every thread ends indefinitively where the BIOS on the CD-ROM packaged with the mobo doesn't resolve the issue. A lot of people have said BIOS flash worked great. My mobo doesn't even recognise the BIOS updates as valid. I checked and checked again that I'm doing the right mobo. Even went so far as to verify that the northbridge and southbridge are the same version and the sata raid controller is the same and the sata non-raid controller is the same.